In the past, packers or bridge plugs have been run into the wellbore on wireline to facilitate rapid positioning and setting. While use of an electric line or wireline packer or plug allows for rapid placement and deployment of such equipment, it requires the use of wireline equipment at the surface which is costly and which creates logistical concerns, particularly in offshore applications.
According to methods used in the past, after running and setting the packer with a wireline, a separate trip has to be made into the wellbore with the tubing-conveyed perforating gun. The need to run the perforating gun on rigid or coiled tubing has, in the past, necessitated this two-trip system when used in combination with packers which are run in on wireline.
Accordingly, it is one of the objects of the present invention to provide a simple system to run in one trip a packer and tubing-conveyed perforating gun. The packer can be easily set in the preferred manner hydraulically such that the setting mechanism releases from the packer, which in turn allows for simple positioning of the perforating gun for subsequent actuation.
Various signaling mechanisms for actuation of downhole tools have been developed. U.S. Pat. No. 5,226,494 indicates a signaling method using pressure-induced strains in tubing suspending a downhole tool to trigger an electronic circuit to actuate the tool. U.S. Pat. No. 5,343,963 also relates to measuring pressure-induced strain in the conveying tubing to trigger the operation of a downhole tool. Yet other devices have been developed that use acoustical signals or pressure pulses transmitted downhole which are received and converted to an electrical signal to actuate a downhole tool.
Creation of a motive pressure force to drive downhole components by initiating a chemical reaction is described in U.S. Pat. No. 5,396,951.
The prior techniques have not approached the simplicity and reliability of the present invention, which facilitates a one-trip operation and allows for considerable savings of rig time and surface equipment.